The Toxicology And Biotransformation For Deoxynivalenol

Mycotoxins were toxic secondary metabolites produced by fungi (molds), wildlycontaminated in raw material and finished product. It would result in mycotoxins poisoningwhen animals were exposed the feed contaminated the mycotoxins. Deoxynivalenol(DON)was a metabolism produced during the growth of Fusarium graminearum. It was a memberof trichothecene family.The aim of the experiment was that The research of toxicology and biotransformationfor deoxynivalenol.TestⅠEffects of low-level dietary deoxynivalenol on growth performance,haematological and histopathological change in the Mice.Forty Kunming mice were divided into four groups, ten mice per group, hall of femaleand male. DON was added into the feed with the concenteation 0, 1, 3 and 5mg kg^-1. Afterfeeding 20 d, the growth performance and blood biochemical, haematological parameters,the weight of immune organ and histopathological change were monitored. At the hightoxin levels (diets 5mg kg^-1), the feed consumption, body weight gains, the weight ofimmune organ including thoracic gland and spleen), red blood cell count, mean corpuscularvolume and blood platelets count were evidently lowered (p＜0.05). The total protein,globulin, urea nitrigen, creatinine and triglyceride in serum were decreased significantly athigh toxin levels (diets 5mg kg^-1), however, the glutamate-pyruvate transaminase, glutamicoxalacetic transaminase, alkali phosphatase and albumin/gtobulion in the serum increasedsignificantly(p＜0.05). The histopathologic examination was observed in different organism.The hepatic congestion, the disappeared obvious boundary between hepatocytesintercellular, the disappearance of cell nucleus and cellular swelling in partial hepatocyteswere observed in liver. The analosis or analosis and hemorrhage of intestinal andstomachal villi were observed in stomach and duodenum. The caps thickening, hyperplasyof spleen trabecula, congestion and partly cell degeneration necrosis were observed inspleen. The muscular degeneration and cardiac muscle cell swelling were observed in Heart. The hylic hemorrhage, extractum in glomcrulus and epithelial cell degeneration wereobserved in kidney. The part hemorrhages were abserved in thymus gland.TestⅡThe cytotoxicity of CHO-K1 and HL-7702 induced by deoxynivalenol.Different final concentrations of DON including 0ng mL^-1,100ng mL^-1, 200ng mL^-1,400ng mL^-1, 800ng mL^-1 were added in the cultures of the CHO-K1 and HL-7702 cell lines.The concentration of IL-2, IL-6 and TNF-a in supernatants were detected by radioimmunity(RI). The results showed that the concentration of IL-2, IL-6 and TNF-a increased at thelow dose (100～200 ng mL-1) in supernatants. However, at the high dose, they wererepressed. The 50% inhibiting concentration (IC50) of the CHO-K1 and HL-7702 cell lineswas 123.5ng mL-1 and 336.2 ng mL-1 respectively. At the high dose of DON, the growthof CHO-K1 and HL-7702 cell lines was inhibited significantly (p＜0.05).TestⅢIsolation and identification of a strain with deoxynivalenolbiotransformation capability.A colony was isolated from soil by inorganic salt culture media added DON(deoxynivalenol) and numbered NJA-1. Bt2a-Bt2b and ITS1-ITS4 were used as primersto amplify theβ-tubulin gene and Internal Transcribed Spacer (ITS) of NJA-1. The size ofamplified fragment was 511bp and 565bp respectively. Contrasting the ITS sequence in thedata base (GertBank+EMBL+DDBJ+PDB), the result showed that the NJA-1 belonged toAspergillus. Contrasting theβ-tubulin gene sequence in data base(GenBank+EMBL+DDBJ+PDB), the result showed that the NJA-1 belonged to AspergiIlustubingensis. Sequence analysis and morphology observation indicated that NJA-1 belongedto Aspergillus tubingensis. Sequence analysis of Bt2a-Bt2b was submitted to GenBank. Theaccess number in data base (GenBank+EMBL+DDBJ+PDB) was DQ902579. Its homologyto Aspergillus tubingensis AY820009 was 99%.TestⅣThe detection of product of the deoxynivalenol biotransformation byNJA-1 strain.The mean detoxification rate of DON is 94.4% after two weeks cultivating. It couldtolerate high concentration of DON up to 40mg L-1 in inorganic salt media. The thin-layerchromatography(TLC), high performance liquid chromatogram(HPLC) and HPLC-MSwere used to detect the product of the DON biotransformation. The product of the DONbiotransformation was blue fluorescence in TLC plate with viltalight lamp at 365nm. Theresults of HPLC showed that the product was absorbent at wave length 218nm andfluorescent (Ex=340, Em=450). The relative molecular weight of transformation product analyzed by HPLC-MS was 314.4 D which was 18.1 D larger than that of DON. Thisshowed that DON could be hydrolyzed by NJA-1.TestⅤThe effect of biotransformatin on deoxynivalenol in feeed by NJA-1 strain.Forty Kunming mice were divided into four groups, ten mice per group, hall of femaleand male. The 5mg kg^-1 DON and 5g kg^-1 NJA-1 strain were added into the feedsimultaneously as JUN+DON group. The 5mg kg^-1 DON and 5g kg^-1 NJA-1 strain wereadded into the feed as DON group and JUN group, respectively. The control group onlyfeeded the basic feed After feeding 20d, the growth performance and blood biochemical,haematological parameters, the weight of immune organ and histopathological change weremonitored. The result showed that the 5g kg^-1 NJA-1 strain was added into feedcontaminated 5mg kg^-1 DON to determinate the effect the biotransformation on DON bythe NJA-1 strain in feed. The result showed that The 5g kg^-1 NJA-1 strain was added intothe feed could alleviate significantly the toxicology caused by 5mg kg^-1 DON. There are notadverse reactions caused by the 5g kg^-1 NJA-1 in feed. The research would establish theapplication of NJA-1 in feed for detoxification in future.